From 2d08290117af916d1c3c46d6ababb0f04833a8f2 Mon Sep 17 00:00:00 2001
From: Oriol <oriol-bugzilla@hotmail.com>
Date: Fri, 15 Apr 2016 09:01:00 -0400
Subject: [PATCH] Bug 1258205 - Make setAttribute throw InvalidCharacterError
 if the attribute already exists. r=baku

---
 dom/base/Element.cpp                                   | 10 ++++------
 .../web-platform/meta/dom/nodes/attributes.html.ini    |  3 ---
 2 files changed, 4 insertions(+), 9 deletions(-)

diff --git a/dom/base/Element.cpp b/dom/base/Element.cpp
index b2bbba8e5fee..41b97a56189b 100644
--- a/dom/base/Element.cpp
+++ b/dom/base/Element.cpp
@@ -1177,14 +1177,12 @@ Element::SetAttribute(const nsAString& aName,
                       const nsAString& aValue,
                       ErrorResult& aError)
 {
+  aError = nsContentUtils::CheckQName(aName, false);
+  if (aError.Failed()) {
+    return;
+  }
   const nsAttrName* name = InternalGetExistingAttrNameFromQName(aName);
-
   if (!name) {
-    aError = nsContentUtils::CheckQName(aName, false);
-    if (aError.Failed()) {
-      return;
-    }
-
     nsCOMPtr<nsIAtom> nameAtom;
     if (IsHTMLElement() && IsInHTMLDocument()) {
       nsAutoString lower;
diff --git a/testing/web-platform/meta/dom/nodes/attributes.html.ini b/testing/web-platform/meta/dom/nodes/attributes.html.ini
index 79bcd8adf5b8..5a49c2cea552 100644
--- a/testing/web-platform/meta/dom/nodes/attributes.html.ini
+++ b/testing/web-platform/meta/dom/nodes/attributes.html.ini
@@ -6,6 +6,3 @@
   [First set attribute is returned with mapped attribute set first]
     expected: FAIL
 
-  [When qualifiedName does not match the Name production, an INVALID_CHARACTER_ERR exception is to be thrown, even if the attribute is already present. (setAttribute)]
-    expected: FAIL
-